SuperPro SPF3404-70K Rear Differential Center Support Bush Kit for RX-8/MX-5 NC

Vehicle Fitment

• 2003-2011/2012 Mazda RX-8 (SE17 chassis)
• 2005/2006-2015 Mazda MX-5 Miata (NC chassis)

Fitment Notes

• Rear differential support bushing, center position
• Sources show minor variation on the exact end year for RX-8 (2011 vs. 2012) and start year for MX-5 NC (2005 vs. 2006), consistent with regional model-year naming differences between the US and other markets - confirm your exact model year against SuperPro's fitment lookup if you're near either boundary
• This bushing does not fit earlier MX-5 generations (NA/NB) - it's specific to the NC-generation differential mount shared with the RX-8

Features

• Premium polyurethane formulated to an above-OE standard for durability and performance
• Tightens the differential-to-chassis connection for more direct power delivery
• Reduces wheel hop and clunking on hard launches and aggressive shifts
• Improves throttle response by minimizing differential movement under load
• Helps maintain consistent drivetrain alignment over time
• Resists heat, oil, and weather-related breakdown that degrades factory rubber bushings
• No increase in NVH (noise, vibration, harshness) versus stock, per SuperPro's engineering design goals
• Suitable for street, track, and competition use

Specifications

• Fitting Position: Rear Differential Support, Center
• Bushing Material: Polyurethane
• Bushing Outer Diameter: 70mm
• Warranty: Lifetime (no exclusions for off-road, track, or competition use)

Included Components

• 2x Polyurethane Bushings
• 2x Steel Tubes

Product Description

The center support bushing on the RX-8 and NC-generation MX-5's rear differential mount takes on the job of isolating the diff from the chassis while resisting the twisting forces that come with hard acceleration and deceleration. When the factory rubber bushing here wears out, the differential can shift under load, showing up as wheel hop on launch, a clunk when power is reapplied after coasting, or a general looseness in how the car puts power down.

The SuperPro SPF3404-70K replaces this bushing with a 70mm polyurethane unit engineered to an above-OE standard, tightening that connection without introducing the harshness or extra noise that lower-quality polyurethane bushings can bring. Because the RX-8 and NC MX-5 share the same rear differential mounting design, this single bushing kit covers both platforms.

This kit suits RX-8 and NC MX-5 owners looking to eliminate driveline slop that's developed from aging rubber, whether the car sees daily driving, autocross, or track use. It's a straightforward bolt-in replacement and a common first step in a broader rear differential/subframe bushing refresh.